Several student and course characteristics were examined in relation to student ratings of instruction. Students at a major Canadian university completed the Universal Student Ratings of Instruction instrument at the end of every course over a three-year period, providing 371,131 student ratings. Analyses of between-group differences indicate that students who attend class often and expect high grades provide high ratings of their instructors (p less than .001). In addition, lab-type courses receive higher ratings than lectures or tutorials, and courses in the social sciences receive higher ratings than courses in the natural sciences (p less than .001). Regression analyses indicated, however, that student and course characteristics explain little variance in student ratings of their instructors (less than 7%). It is concluded that student ratings are more related to teaching instruction and behavior of the instructor than to these variables.